Concentration measurements of OH and equilibrium analysis in a laminar methane-air diffusion flame

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Combustion and Flame; (USA)

DOI:https://doi.org/10.1016/0010-2180(90)90146-I· OSTI ID:6774020

Smyth, K C; Tjossem, P J.H. ^[1]; Hamins, A; Miller, J H ^[2]

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1. National Bureau of Standards, Washington, DC (USA). Center for Fire Research
2. George Washington Univ., Washington, DC (USA). Dept. of Chemistry

Absolute concentration measurements of hydroxyl radical have been made in a laminar, co-flowing methane-air diffusion flame using laser absorption and laser-induced fluorescence methods to probe the {ital A}{sup 2}{Sigma}{sup +} {l arrow} {ital X}{sup 2}{Pi}{sub {ital i}} transition. The maximum OH {center dot} concentration is found to be 1.8 {+-} 0.2 {times} 10{sup 16} cm{sup {minus} 3} (mole fraction = 5.0 {times} 10{sup {minus} 3}) at a temperature of 2080 K, which is twice the value calculated assuming local total equilibrium but less than half that predicted from partial equilibrium (O{sub 2} + H{sub 2} {l reversible} 2OH {center dot}). Evidence is presented that in general partial equilibrium does not exist for the fast, bimolecular chain branching and radical shuffle reactions in this flame. The overall chemical production-destruction rate profile of OH {center dot} has been determined, as well as the rates of hydrogen abstraction reactions by hydroxyl radical to form the vinyl and ethynyl radicals. These results are used to identify the most rapid routes for the production of radical species important in chemical growth processes.

• OSTI ID: 6774020
• Journal Information: Combustion and Flame; (USA), Journal Name: Combustion and Flame; (USA) Vol. 79:3; ISSN CBFMA; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
092000* -- Biomass Fuels-- Combustion-- (1990-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400800 -- Combustion
Pyrolysis
& High-Temperature Chemistry
AIR FLOW
ALKANES
CHEMICAL REACTION KINETICS
EQUILIBRIUM
FLAME PROPAGATION
FLAMES
FLUID FLOW
GAS FLOW
HYDROCARBONS
HYDROXYL RADICALS
KINETICS
LAMINAR FLOW
LASER SPECTROSCOPY
METHANE
ORGANIC COMPOUNDS
RADICALS
REACTION KINETICS
SPECTROSCOPY